use IPC::Run3 'run3';
sub myrun {
	my ($cmd) = @_;
	run3 $cmd, undef, \my $out, \my $err
		or die "run3 failed";
	my $rv=$?;
	chomp($err);
	die "command '$$cmd[0]' wrote to STDERR: '$err'" if $err;
	die "command '$$cmd[0]' exit value indicates error: \$?=$rv"
		unless $rv==0;
	return $out;
}